The National Map includes orthoimagery (aerial photographs), elevation, geographic names, hydrography, boundaries, transportation, structures, and land cover.

1. Nat'l Map FAQs
2. Nat'l Map REST services
3. Nat'l Map Download client

   

a.k.a. 'the blue lines'

1. Primary purpose: to portray water on The National Map (non-directed network)
2. Drainage network including rivers, streams, canals, lakes, ponds, coastline, dams, and streamgages
3. Available in 1:1,000,000; 1:100,000 ('medium res'); and 1:24,000 ('high res' or 'local res').
4. Used in conjunction with USGS Watershed Boundary Dataset, and 3D Elevation Program (3DEP) to create the NHD+

   

NHD and WBD FAQs

1. Download from nhd.usgs.gov
2. K. Bocinsky's FedData R package
3. Nat'l Map REST services
4. Nat'l Map Download client

"Can I deal with NHD in the cloud?"

1. NHDPlus is an integrated suite of application-ready geospatial data sets that incorporate many of the best features of the National Hydrography Dataset (NHD), the National Elevation Dataset (NED), and the Watershed Boundary Dataset (WBD).
2. NHD+ V2 available for 1:100,000 NHD; high-res NHD+ in development
3. USGS and EPA contract Horizon Systems to build and maintain NHD+

Some rules apply

1. Reaches are directed, and each reach has 0 or 1 inlet and exactly 1 outlet
2. NHD+ catchments are 1:1 for each internodal NHD reach
3. To generate the NHD+, 'hydroenforcement' is applied: Water must flow along flow lines
4. WBD is used to define the upstream boundary for NHD+ headwater catchments
5. Digital elevation is used to define NHD+ catchment 'walls'

Data download from NHD+ V2 Horizon Systems

NHD+ documentation

Share your expertise

1. How do you access NHD data?

2. How do you access NHD+ data?